#include "stdafx.h"
#include "ApiUtils.h"

namespace Utils
{
	namespace ApiUtils
	{
		void SaveScreenshotToTheFile(const std::wstring& path)
		{
            // Source[1]
            HDC hdcScr, hdcMem;
            HBITMAP hbmScr;
            BITMAP bmp;
            int iXRes, iYRes;

            // Create a normal DC and a memory DC for the entire screen. The
            // normal DC provides a "snapshot" of the screen contents. The
            // memory DC keeps a copy of this "snapshot" in the associated
            // bitmap.
            hdcScr = CreateDCW(L"DISPLAY", NULL, NULL, NULL);
            hdcMem = CreateCompatibleDC(hdcScr);

            iXRes = GetDeviceCaps(hdcScr, HORZRES);
            iYRes = GetDeviceCaps(hdcScr, VERTRES);

            // Create a compatible bitmap for hdcScreen.
            hbmScr = CreateCompatibleBitmap(hdcScr, iXRes, iYRes);
            if (hbmScr == 0) return;

            // Select the bitmaps into the compatible DC.
            if (!SelectObject(hdcMem, hbmScr)) return;

            // Copy color data for the entire display into a
            // bitmap that is selected into a compatible DC.
            if (!StretchBlt(hdcMem,
                0, 0, iXRes, iYRes,
                hdcScr,
                0, 0, iXRes, iYRes,
                SRCCOPY))

                return;

            // Source[2]
            PBITMAPINFO pbmi;
            WORD cClrBits;

            // Retrieve the bitmap's color format, width, and height.
            if (!GetObject(hbmScr, sizeof(BITMAP), (LPSTR) &bmp)) return ;

            // Convert the color format to a count of bits.
            cClrBits = (WORD)(bmp.bmPlanes * bmp.bmBitsPixel);
            if (cClrBits == 1)
                cClrBits = 1;
            else if (cClrBits <= 4)
                cClrBits = 4;
            else if (cClrBits <= 8)
                cClrBits = 8;
            else if (cClrBits <= 16)
                cClrBits = 16;
            else if (cClrBits <= 24)
                cClrBits = 24;
            else cClrBits = 32;

            // Allocate memory for the BITMAPINFO structure. (This structure
            // contains a BITMAPINFOHEADER structure and an array of RGBQUAD
            // data structures.)
            if (cClrBits != 24)
                pbmi = (PBITMAPINFO) LocalAlloc(LPTR,
                        sizeof(BITMAPINFOHEADER) +
                        sizeof(RGBQUAD) * (1 << cClrBits));

            // There is no RGBQUAD array for the 24-bit-per-pixel format.
            else
                pbmi = (PBITMAPINFO) LocalAlloc(LPTR,
                        sizeof(BITMAPINFOHEADER));

            // Initialize the fields in the BITMAPINFO structure.
            pbmi->bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
            pbmi->bmiHeader.biWidth = bmp.bmWidth;
            pbmi->bmiHeader.biHeight = bmp.bmHeight;
            pbmi->bmiHeader.biPlanes = bmp.bmPlanes;
            pbmi->bmiHeader.biBitCount = bmp.bmBitsPixel;
            if (cClrBits < 24)
                pbmi->bmiHeader.biClrUsed = (1 << cClrBits);

            // If the bitmap is not compressed, set the BI_RGB flag.
            pbmi->bmiHeader.biCompression = BI_RGB;

            // Compute the number of bytes in the array of color
            // indices and store the result in biSizeImage.
            pbmi->bmiHeader.biSizeImage = (pbmi->bmiHeader.biWidth + 7) / 8
                                            * pbmi->bmiHeader.biHeight * cClrBits;

            // Set biClrImportant to 0, indicating that all of the
            // device colors are important.
            pbmi->bmiHeader.biClrImportant = 0;

            HANDLE hf;                  // file handle
            BITMAPFILEHEADER hdr;       // bitmap file-header
            PBITMAPINFOHEADER pbih;     // bitmap info-header
            LPBYTE lpBits;              // memory pointer
            DWORD dwTotal;              // total count of bytes
            DWORD cb;                   // incremental count of bytes
            BYTE *hp;                   // byte pointer
            DWORD dwTmp;

            pbih = (PBITMAPINFOHEADER) pbmi;
            lpBits = (LPBYTE) GlobalAlloc(GMEM_FIXED, pbih->biSizeImage);

            if (!lpBits) return ;

            // Retrieve the color table (RGBQUAD array) and the bits
            // (array of palette indices) from the DIB.
            if (!GetDIBits(hdcMem, hbmScr, 0, (WORD) pbih->biHeight, lpBits, pbmi, DIB_RGB_COLORS)) return;

            // Create the .BMP file.
			hf = CreateFile(path.c_str(),
                            GENERIC_READ | GENERIC_WRITE,
                            (DWORD) 0,
                            NULL,
                            CREATE_ALWAYS,
                            FILE_ATTRIBUTE_NORMAL,
                            (HANDLE) NULL);
            if (hf == INVALID_HANDLE_VALUE) return;

            hdr.bfType = 0x4d42;        // 0x42 = "B" 0x4d = "M"

            // Compute the size of the entire file.
            hdr.bfSize = (DWORD) (sizeof(BITMAPFILEHEADER) +
                         pbih->biSize + pbih->biClrUsed *
                         sizeof(RGBQUAD) + pbih->biSizeImage);
            hdr.bfReserved1 = 0;
            hdr.bfReserved2 = 0;

            // Compute the offset to the array of color indices.
            hdr.bfOffBits = (DWORD) sizeof(BITMAPFILEHEADER) +
                            pbih->biSize + pbih->biClrUsed *
                            sizeof (RGBQUAD);

            // Copy the BITMAPFILEHEADER into the .BMP file.
            if (!WriteFile(hf, (LPVOID) &hdr, sizeof(BITMAPFILEHEADER), (LPDWORD) &dwTmp, NULL)) return;

            // Copy the BITMAPINFOHEADER and RGBQUAD array into the file.
            if (!WriteFile(hf, (LPVOID) pbih, sizeof(BITMAPINFOHEADER)
                        + pbih->biClrUsed * sizeof (RGBQUAD),
                        (LPDWORD) &dwTmp, NULL))
                return;

            // Copy the array of color indices into the .BMP file.
            dwTotal = cb = pbih->biSizeImage;
            hp = lpBits;
            if (!WriteFile(hf, (LPSTR) hp, (int) cb, (LPDWORD) &dwTmp, NULL)) return;

            // Close the .BMP file.
            if (!CloseHandle(hf)) return;

            // Free memory.
            GlobalFree((HGLOBAL)lpBits);
            ReleaseDC(0, hdcScr);
            ReleaseDC(0, hdcMem);

		}
	}
}